Diagnosis of the cause of pain in the soft tissues is usually based on the location of the pain and the details of how it developed. In some cases, there may be a specific injury, though this is often just an aggravation of a recurring problem. In either case, understanding the activity being performed at the time the pain developed is an important factor. Pain located at the site of a tendinous structure, often described as an ache, is usually due to tendinitis or degeneration of the tendon. Localized trauma, such as an acute ligament sprain, produces pain and swelling, often with discoloration of the skin. Pain from a tear of the tendon or ligamentous structure can be severe, though there are many people with chronic tendon problems who develop little acute pain, despite significant loss of function. A giving way feeling in a joint often indicates a mechanical problem with the joint or surrounding soft tissues. Pain or aching in the soles of the feet may be due to various problems with the bones or arthritis in the small joints of the midfoot and may be related to increased activity or time spent on one’s feet.
Foot and ankle pain is a common clinical problem. As in any other part of the body, the pain can have a wide range of causes. This makes effectively diagnosing the cause of the pain the first step in planning appropriate treatment. The many possible causes of foot and ankle pain can be separated into those that cause pain in the soft tissues, such as tendinitis or nerve compression, and those that cause pain in the joints. Arthritis is a frequent example of a condition that causes pain in both the joints and the soft tissues. The patterns of arthritis in the foot and ankle are often complex and may be associated with significant deformity.
Overview of Foot and Ankle Pain
New Problem Oriented Assessment of the Foot and Ankle Gilbart et al have discussed a method of understanding and classifying foot and ankle problems which is useful in diagnosing the structural damage and biomechanical effects of the problem, and is a good foundation to a new problem oriented assessment of the foot and ankle. Through an understanding of the patient’s pain provocation activity and its effects, a systematic examination, and special investigations when needed, it encourages a decision making process to reach an accurate diagnosis. The first step of this process is a thorough Patient History which will provide indications and contra-indications for certain diagnoses, as well as patient specific goals and expectations. This will lead into a well planned Clinical Examination which can be enhanced with the use of regional nerve and joint blocks to create a replica of the patient’s pain provocation activity. The findings can be best understood through foot and ankle specific radiographs and ultrasound, and if still indicated, an MRI investigation with referral to an appropriate foot and ankle subspecialist. This approach is beneficial for any practitioner treating musculoskeletal foot and ankle problems, and is mostly suitable to a foot and ankle surgeon treating surgical conditions.
The anatomic complexity of the foot and ankle makes diagnosis and treatment of foot and ankle injuries challenging. The biomechanical function of the foot and ankle is essential in providing a stable base of support and mobility for the body. The foot and ankle is made up of 26 bones and 33 joints forming two mobile segments, which provide adaptability to various surfaces. The multiple muscles and two crossing tendons of the foot and leg that insert into the foot serve to provide the power and coordination for foot and ankle motion. It is the powerful and coordinated function of these muscles that enable the normal gait. The many functions of the foot and ankle are further enhanced by its unique and intricate anatomical design that provides both flexibility and support. This design has made the foot and ankle vulnerable to a wide variety of acute injuries and chronic conditions with resultant degenerative changes. Primary care physicians and musculoskeletal specialists should have a logical and systematic approach in the evaluation and diagnosis of foot and ankle injuries to understand the foot and ankle mechanics and to diagnose the orthopaedic foot and ankle problem. A well organized and systematic evaluation and diagnostic process will improve the understanding of foot and ankle pathology, its structural damage and its biomechanical effects. This understanding will then facilitate a well informed decision regarding the most appropriate treatment.
Importance of Diagnosing Foot and Ankle Pain
The foot and ankle are quite complex in terms of structure and function. The diagnosis may not be as simple as finding out which structure is damaged. Due to the intricacy of the foot and ankle, often the exact spot of the patient’s pain may be a poor indicator of the location of the problem. The sense of location can sometimes be misleading. This is true, for example, of a stress fracture in the foot. Often the patient is unable to pinpoint the exact location of the pain. Failure to diagnose or making diagnosis errors can be prevented by taking a comprehensive look at the patient’s problem and ruling out possibilities step by step. Picking the correct diagnosis needs careful correlation of patient symptoms, past history, and the clinical findings from the specific tests and examinations done for the foot and ankle pain.
Diagnosis is the key to the management of patients with foot and ankle pain. It is essential in the formation of a treatment plan and expected outcome. An accurate diagnosis serves to direct the treatment and also helps to predict the duration before the return to activities of daily living. Failure to diagnose leads to the failure of treatment. Wrong diagnosis may lead to worsening of the condition. An accurate diagnosis is also needed to inform the patient and, having understood the problem, it is likely to increase the patient’s compliance with the treatment.
Diagnosing the foot and ankle pain is of utmost importance. Many people suffer from this condition. If left untreated or if the treatment is not directed at the underlying cause of the problem, it may develop into a chronic problem that may have a significant impact on the quality of life and ability to function in everyday activities.
Physical Examination
Step two in the physical examination is palpation of anatomical landmarks and areas of pain to confirm the presence of soft tissue and bony structures. Range of motion and specific stress tests will be discussed in subsequent sections. Visual and sensory examination takes place during the examination of each anatomical area. This is an important time to compare the suspected painful side to the asymptomatic side in order to differentiate between a previous problem or congenital abnormality. Measures of x-ray deformity, swelling, and/or erythema can be compared to previous examinations using written documentation and photography. A goniometer can be used to quantify range of motion and compare it to normative values. An examiner must remain open-minded and attempt to correlate the information obtained from inspection and observation to the patient’s history and/or mechanism of injury to provide a differential diagnosis for the problem. During neurologic assessment, the examiner tests motor strength, the specific nerve’s sensory distribution area, and finally reflex testing to provide a clear understanding of the nerve function and locate the affected neural lesion. The examination is crucial for the diagnosis of neural and musculoskeletal problems and will lead to appropriate diagnostic imaging and/or special tests in the future.
A physical examination is conducted in a systematic manner. The major purpose of the examination is to assess the function of the foot and/or ankle. Major focus is given to gait (the manner in which a person walks) during initial observation. Often a patient’s gait can be altered due to pain, with the affected limb demonstrating either a decrease in weight bearing or inability to perform heel or toe off during stance phase. A limp can be observed during initial contact and loading response phase if there is pain during heel strike. Stance phase can reveal a decrease in weight bearing through increased use of an assistive device such as a cane or crutch. Single limb balance and gait speed often decrease in older adults. The examiner must watch and listen carefully to the patient during the gait analysis with the examination of non-verbal body language being just as important as historical information obtained from the patient. An abnormal gait pattern can often lead an examiner to a specific painful region of foot and/or ankle in order to determine the cause. For example, a patient suffering from peroneal tendon pathology may demonstrate an inability to raise their body over the first ray during push off and will have a dropped metatarsal. As a result, they will often compensate by obtaining increased lateral foot purchase during stance phase in order to obtain more leverage. An antalgic (painful) gait is often involuntary and is the body’s way of avoiding a specific painful movement. This type of gait can be observed if the painful condition has been acute and the person is guarding the limb to prevent further damage. An involuntary limp from pain will often decrease when the examiner injects anesthetic into the suspected painful region and asks the patient to resume walking in order to assess for functional improvement.
Visual Inspection and Observation
With the patient now seated, the examiner inspects the forefoot. The toes should be observed for contractures in either dorsal or plantar directions. Hammer toes are flexion deformities of the PIP joint while mallet toes are flexion deformities of the DIP joint. Claw toes are a combination of PIP flexion and DIP extension. Hallux abducto valgus is a lateral deviation of the great toe with a resultant prominence of the first metatarsal head at the medial aspect of the forefoot. A callus often forms in this area as a result of friction from shoes. This is a common and often painful deformity of the forefoot. The lesser toes may also have prominence of the metatarsal heads infero-laterally due to splay of the forefoot and possible hypermobility of the MTP joints.
Visual inspection of the foot begins with the patient standing and walking. Standing, the examiner looks at the relationship of the hindfoot to the forefoot. A normal valgus (hindfoot deviated away from the midline relative to the forefoot) appears as an arch and elevation of the instep. This is easily observed from behind the patient. A varus hindfoot is difficult to appreciate without experience. The examiner should also look at the general shape of the foot. It may be long, with a flexible flatfoot deformity, or a high arched cavus foot. The flexible flatfoot is a very common condition of the foot and is usually painless, but can lead to arthritic changes in the supportive hindfoot structures. Rigid flatfeet usually result from tarsal coalition and are often painful.
Palpation and Range of Motion Testing
An understanding of lower extremity joint and normal range of motion is essential to make comparisons between the symptomatic and asymptomatic sides of the body. In comparison to the uninjured side, assessment of the injured side can aid in identifying a variety of pathologic conditions. Increased or decreased joint flexibility may indicate muscle weakness or a limitation in soft tissue flexibility. A common example of this is the loss of ankle dorsiflexion range of motion following an ankle sprain, which is an important risk factor for the recurrence of the injury. Quotation of a specific ligament or tendon can lead to chronic joint instability and swelling.
Palpation of the painful area can help to determine the specific nature of the injury, but the location and intensity of the pain, as well as the patient’s response to palpation, must be compared to the uninvolved side. Pain and tenderness over a specific bone can indicate a possible fracture, while pain localized to a specific ligament or tendon can indicate a sprain or strain. Joint fusion will produce pain at the end of its normal range of motion and pain throughout the range of motion with an arthritic joint. Assessment of the quality of tissues around the injury site can also provide valuable diagnostic information. Swelling in the area can indicate internal damage to a joint, ligament, or tendon, or other damage to local tissues. Localized loss of tissues can reveal a rupture or avulsion of a muscle tendon, while a feeling of increased warmth in the area can be an indication of inflammation.
Neurological Assessment
Neurological testing typically occurs after inspection, palpation, and range of motion testing. These tests measure the functioning of the nerves. The only way to accurately measure nerve function is by EMG. It tests the electrical activity of a muscle and helps determine if muscle weakness is related to a nerve or muscle disorder. EMG can also rule out other conditions or confirm a suspected diagnosis. Although EMG may be the most accurate way to measure nerve function, it is often saved as a last option and many times not necessary to properly diagnose conditions. Other ways to measure nerve function include testing sensation, testing reflexes, and muscle testing. Test sensation can be performed using a pinwheel to determine if a patient feels sharp or dull, hot or cold. These results are compared to the opposite foot and help determine where and what type of nerve damage has occurred. Testing reflexes will be done by comparing the reflex to the opposite foot and using a reflex hammer to determine if a reflex is normal, decreased, or absent. This may help confirm suspicion of nerve damage to a certain area. Lastly, muscle testing can be done using a handheld dynamometer. This may help determine muscle strength and if muscle weakness is due to a nerve or muscle disorder. These tests are helpful in determining the location and severity of nerve damage and may help rule out other conditions.
Diagnostic Imaging
A CT (computer tomography) scan is similar to an MRI in that it provides detailed images of any part of the body. However, a CT provides detailed images of more solid material in the body such as bone. This form of imaging usually takes 5-10 minutes and is becoming more useful since a new cost-effective technique was developed. Often a CT scan will be used to assess the contributors of a complicated fracture and therefore plan what action is to be taken. CT can also be used to assess the position of a bone after a fracture or ligament injury to provide a better understanding of what damage may have been done. It is also becoming useful to plan for orthopedic surgery.
MRIs are good for detecting soft tissue abnormalities such as ligament or tendon injury, cartilage loss, presence of cysts or tumors, and infections. They are also good for diagnosing problems in the bone marrow which x-rays cannot demonstrate. Due to the MRI showing images slice by slice, it is very useful in determining how severe an injury or condition may be. An MRI is very high in sensitivity and specificity; however, the high cost and sometimes limited availability can be a disadvantage.
It is useful to obtain x-rays of both feet as comparison between an affected and unaffected side can be useful. MRI (magnetic resonance imaging) uses a magnetic field and radio waves to obtain cross-sectional images of the body and is helpful in creating images of soft tissues. An MRI is more complex than x-rays and therefore takes longer. This is becoming the most widely used form of imaging for the foot and ankle.
X-ray is usually the first form of imaging used and can provide useful information in diagnosing many different foot and ankle problems. However, many problems do not show up on x-ray. X-rays are useful as they provide information on alignment of bones, fractures, dislocations, and the presence of foreign objects such as glass or gravel. They only give a 2D image and therefore are not useful to diagnose problems in the joint.
X-Ray
An X-ray is a form of electromagnetic radiation that is used to create images of a patient’s internal anatomy for the purpose of diagnosis. X-rays can be transmitted through the body in much the same way as light, but because they are less scattered by soft tissue, they are able to penetrate denser substances. While the majority of X-rays are absorbed by the body, less dense material such as bones and cartilage allows more of the X-ray to pass through and will be recorded by a detector, creating an image. Hard tissues or foreign bodies will create a silhouette on the film due to their ability to block the passage of X-rays. X-rays are often used as a first line of investigation of musculoskeletal problems. While providing only 2-dimensional images and low resolution of soft tissue, X-rays are relatively cheap and the speed at which they can be performed makes them a useful tool in ruling out more serious underlying issues or referring to other forms of imaging. X-rays can be used to investigate deformities or injuries to bones and joints, as well as being able to detect various forms of arthritis and infections. X-rays can also be used to track the progression of a patient’s condition and the efficacy of treatment.
MRI
Due to the magnetic field created by the MRI machine, patients with certain implanted medical devices should not have an MRI. Be sure to tell your doctor if you have any metal or electronic devices in your body because they may pose a risk. Also, patients with claustrophobia may find it difficult to undergo an MRI because the test is done in a confined space. Open MRI machines, which have a larger opening and are less confining, are available for those who cannot tolerate a conventional MRI.
An MRI is a large machine that has a round “tube” in the middle of it. The patient lies on a bed that slides into the tunnel of the magnet. The machine creates a strong magnetic field around the body, and radio waves are directed at the body. The procedure is non-invasive and painless. The radio waves produce a faint signal that creates a detailed picture of the area being examined. During the MRI, the patient must remain very still to avoid blurring the image.
The MRI gives a very clear view of the soft tissues of the body and is particularly useful to help diagnose stress fractures in their early state. It can also help to explain the cause of unexplained pain or swelling in the foot, particularly if it is being felt deep within the soft tissues. Because an MRI shows the soft tissues so clearly, it is the most specific test to determine whether there is a torn ligament or tendon in the foot or ankle.
Magnetic Resonance Imaging (MRI) provides a clear picture of the soft tissues of the body. It is therefore often used to further explore an abnormality found to affect the soft tissues on an X-Ray.
CT Scan
CT uses X-rays and a computer to produce images of the body. In CT, a series of cross-sectional pictures of the area being studied are taken and then assembled into a 3-dimensional image. In comparison, a standard X-ray is like viewing a single slice from a loaf of bread. CT is used for a variety of foot problems, often when more information is needed about a specific area. An example is a fracture that does not show up clearly on X-rays. Fractures, bone infections, and arthritis, as well as the extent of soft tissue injury, are all examples of problems identified more clearly on CT. In complex foot and ankle trauma and in patients with metallic hardware post-surgery, CT can provide a picture of the degree of healing. This is particularly useful for surgical planning. CT is a painless procedure; however, due to the necessity for increased detail in bony images, a higher level of radiation used in CT can slightly increase the risk of a possible harmful effect to the unborn fetus or in a pediatric patient. It is recommended to obtain CT imaging in this situation only if the potential benefit of imaging clearly outweighs the risks. The duration of the examination will vary between 5-30 minutes. All imaging is reviewed and reported by a Radiologist, and the results are forwarded to the referring Physician.
Laboratory Tests
Joint fluid is necessary for normal joint mobility. Ankle joint fluid is essential for normal ankle movement. In the foot, joint fluid often collects in a single joint when that joint is diseased, such as the big toe joint. Joint fluid can be extracted using a needle and syringe. An ultrasound scan can assist in localizing the position of the needle in relation to the joint during this procedure. This is commonly used for the big toe and ankle joints, which are deep and not easily palpable. The ultrasound itself can be diagnostic for certain conditions. For example, the presence of inflammatory joint fluid in a painful ankle joint indicates inflammatory arthritis, with rheumatoid arthritis being the most common form.
Blood tests can be helpful in diagnosing foot and ankle problems. They can indicate the presence of systemic diseases if symptoms of foot or ankle pain are present. If a local foot or ankle problem is suspected, knowledge of the patient’s systemic conditions can guide the use of specific radiographs. For instance, if gout is suspected as a cause of joint pain, specific x-ray findings combined with blood tests can increase the certainty of diagnosis.
Blood Tests
ESR and CRP: ESR stands for Erythrocyte Sedimentation Rate and CRP stands for C Reactive Protein. These are both measures of inflammation in the body. If there is a high level of inflammation, for example as occurs in a systemic disease or an infected joint, then these markers will be raised. Both tests involve putting the blood in a machine or tube and measuring the distance or rate at which the red cells fall, or the level of certain proteins in the blood. A raised ESR or CRP does not give a specific diagnosis, but when there is clinical suspicion of a high level of inflammation, then a raised ESR or CRP may act to confirm the diagnosis. The tests are reliable and are commonly used in diseases such as gout or pseudogout, rheumatoid and osteoarthritis and systemic diseases. Usually the tests are done in a clinic or hospital and results can be reported on the same day if they are done in an onsite laboratory.
Full Blood Count: This is a very common test and gives information on the cell count of the blood. It can be useful in the detection of various conditions, particularly systemic diseases that may not have an obvious clinical presentation. For example, rheumatoid arthritis and other types of inflammatory arthritis can sometimes cause a condition called anemia, which is often detected on a full blood count. This test can be performed in most clinics and hospitals and can be reported the same day that the blood is taken. It usually represents a good starting point in the investigation of a systemic illness that may be associated with a foot and ankle complaint.
There are many different blood tests (also called laboratory tests) that can be useful in the diagnosis and management of certain foot and ankle conditions. But it is important that any blood test is interpreted within the context of the full case history, examination and any other necessary investigations. Sometimes the result can be misleading and if the clinical picture does not fit with the result, then it may be that the test should be repeated or even disregarded as a means of making a diagnosis.
4.2. Joint Fluid Analysis
Microscopic analysis: The fluid is placed onto a glass slide and into a centrifuge which spins the fluid very quickly and forces any cells to the bottom. The cells are then examined under a microscope. This can show the presence of crystals which may indicate gout or pseudogout, or an abnormal number of the various types of white blood cells.
Chemical tests: This can include testing for levels of uric acid which can cause gout, or glucose levels which can help to diagnose rheumatoid arthritis. Many of the tests are non-specific and only give tentative clues to the underlying problem.
Cell count: A sample of fluid is placed on a special counting chamber and the number of red blood cells and white blood cells is counted. Abnormal numbers of blood cells can be caused by many different conditions.
Looking at the fluid: The fluid will be examined to see if it is bloody or cloudy, and whether it has the normal straw-like color. These are clues to the possible causes of joint problems.
The fluid is sent to a lab for testing and the results are usually available in 1 to 3 days. The tests which are done can include the following:
A small amount of fluid is taken from a joint. This is most easily done by placing a needle into the joint space. For example, if the knee is being tested, the healthcare provider first cleans the skin around the knee with antiseptic. Next, a numbing medicine (local anesthetic) is injected into the skin around the knee. Then, a needle is placed into the joint space, and fluid is drawn into the syringe. Two or more samples of fluid may be taken so that they can be compared. After the needle is removed, the puncture site is covered with a bandage.
Joint fluid analysis is a group of tests done on the synovial (joint) fluid to look for various problems of the joints. The tests help find the cause of joint pain or swelling. The test is usually done on the knee, but it may also be done on other joints.
